The use of ceramic beads and balls in milling and grinding minerals and inorganic substances is known. The beads and balls are preferably formed of ceramic materials that exhibit high toughness, high hardness, good strength, and high wear resistance. It is known to use beads and balls that are formed of alumina or zirconia that is stabilized or partially stabilized by means of yttrium oxide, cerium oxide, or magnesium oxide (among others). It is also known to use beads formed of alumina-zirconia-silica and zirconium silicate.
The present invention provides grinding media and, more specifically, beads formed of an alumina-zirconia composition having improved hardness and wear resistance, as compared to milling media known heretofore. A composition with better properties than conventional alumina-zirconia-silica is also demonstrated.